River
Onon River
1,032 km from source to mouth · Russia and Mongolia.
Russia and MongoliaFlows into Shilka
In numbers
Length
1,032km
Average flow
190m³/s
Basin
96,200km²
Drop
986m
from 1,481 m to 495 m
Countries
2
The journey
From source to mouth
1,032 km of river and 9 stops on the way: 2 towns and cities on its banks, dams, bridges and the tributaries that feed it.
- 0 kmSourceat 1,481 m
- 347 kmBaldzhatributary
- 371 kmAgutsatributary
- 407 kmKyratributary
- 611 kmIlyatributary
- 778 kmBorzya Rivertributary
- 809 kmYasnogorsk8,873 people
- 819 kmOlovyannaya8,247 people
- 892 kmUndatributary
- 923 kmAga Rivertributary
- 1,032 kmShilkaat 495 m
Water level along the river (RiverATLAS; the height is exaggerated). Towns: GeoNames and Wikidata; bridges, dams and tributaries: Wikidata.
River in Mongolia and Russia
At the mouth it carries 191 m³/s on average: an Olympic pool every 13 seconds. It drops from 1,481 m to 495 m, 1.0 m per kilometre on average. Its basin covers 96,200 km², about the size of KR. 676,000 people live in it. Highest water: from August to September; lowest: from January to April. No large dam holds it back: it is one of the world's free-flowing rivers.
Where to start
- YasnogorskLargest city on its banks · 8,873 people
- Manzhouli Xijiao Airport (NZH)Nearest airport with scheduled flights, 186 km from the city
- On the water4 ferry piers, marinas, boat rentals and boat ramps along the river (OpenStreetMap)
- From June to AugustThe best months to visit
Onon River, month by month
Highest water: from August to September
Lowest water: from January to April. Freezing months (average below −4 °C): from November to March. Best months to visit: from June to August.
From about 140 m³/s in the lowest month to 840 m³/s in the highest. An estimate: the monthly flow is modelled from the lowest and highest months of WaterGAP (RiverATLAS, 1971–2000) and the rain and snow along the river (WorldClim). Dams change the real rhythm. The chip is the average air temperature; below it, the month's rain.
Plan the trip
Plan the trip: boat trips, a bed by the river, a car
Some links above are affiliate links: if you book through them we may earn a commission, at no extra cost to you. It never changes what the data on this page says.
The basin
Onon River: the basin in numbers
129,598 km² of land send their water to this river. This is what lives on it.
- 676,000people live in the basin
- 5/km²people per km²
- 1,047maverage altitude of the basin
- 373mmof rain a year (basin average)
- -2.6°Caverage air temperature
- 8%protected areas
- 0.1%covered by lakes
- 25%permafrost
What covers the basin
- 39% Forest
- 9% Cropland
- 36% Pasture
RiverATLAS (HydroATLAS v1.0, CC BY 4.0): land cover, people, protected areas, glaciers and dams over the whole basin upstream of the mouth.
Along the river
Onon River: what you find on the way
- 4Ferry piers
From OpenStreetMap, within 2.5 km of the river. Not mapped is not the same as not there.
From space
The source and the mouth, seen from orbit


Sentinel-2 cloudless 2016 by EOX IT Services GmbH (contains modified Copernicus Sentinel data 2016), CC BY 4.0. The glowing line is the river as drawn by RiverATLAS.
Photos
Onon River in pictures
Tributaries
Where it flows, and what flows into it
It flows into
ShilkaTributaries (8)
Also: Borzya River, Aga River, Unda, Baldzha, Ilya, Kyra, Agutsa, Turga
In the same basin
Where these numbers come from
| Name, length, places | Wikidata (Q206694) · CC0 |
|---|---|
| Course, profile, basin | RiverATLAS v1.0 (HydroATLAS, Linke et al. 2019) · CC BY 4.0 — followed from the source to the mouth given by Wikidata |
| Flow | WaterGAP (RiverATLAS), 1971–2000 · CC BY 4.0 |
| Climate along the river | WorldClim (RiverATLAS), 1970–2000 · CC BY 4.0 |
| Towns, bridges, dams | Wikidata · CC0; GeoNames · CC BY 4.0 |
| Along the river | © OpenStreetMap contributors · ODbL |
| Images | EOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons |
Every source and licence is on the data sources page.
The family
Do you prefer beaches, lakes, mountains, waterfalls, islands, rivers or canyons?
Same idea, other landscapes: field atlases built on open data, month by month, in seven languages.



